# deno_ops `proc_macro` for generating highly optimized V8 functions from Deno ops. ```rust // Declare an op. #[op(fast)] pub fn op_add(_: &mut OpState, a: i32, b: i32) -> i32 { a + b } // Register with an extension. Extension::builder() .ops(vec![op_add::decl()]) .build(); ``` ## Performance The macro can optimize away code, short circuit fast paths and generate a Fast API impl. Cases where code is optimized away: - `-> ()` skips serde_v8 and `rv.set` calls. - `-> Result<(), E>` skips serde_v8 and `rv.set` calls for `Ok()` branch. - `-> ResourceId` or `-> [int]` types will use specialized method like `v8::ReturnValue::set_uint32`. A fast path for SMI. - `-> Result` or `-> Result<[int], E>` types will be optimized like above for the `Ok()` branch. ### Fast calls The macro will infer and try to auto generate V8 fast API call trait impl for `sync` ops with: - arguments: integers / `&mut OpState` - return_type: integers The `#[op(fast)]` attribute shoukd be used to enforce fast call generation at compile time. Trait gen for `async` ops & a ZeroCopyBuf equivalent type is planned and will be added soon.